New intermediates of the anthraquinone series



United States Patent- Q NEW INTERMEDIATES OF THE ANTHRAQUINONE SERIESHarry Edward Westlake, Jr., Somerville, and William Baptist Hardy, BoundBrook, N. J assignors to American Cyanamid Company, New York, N. Y., acorporation of Maine No Drawing. Application June 10, 1952, Serial No.292,714 e 3 Claims. (Cl. 260-381) This invention relates to newcompounds of the anthraquinoneseries, and more particularly, it relatesto substituted anthraquinones: T

which have a halogen atom in the 1-position, a f'nitro group in the2-position, and a second nitro group in" 5 Westlake, Serial No. 289,204,filed May 21, 1952, now

Patent No. 2,655,502.

We have found that one may nitratejl-halo; 2-nitroanthraquinone toproduce a mixture of only two isomers, namely,1-chloro-2,5-dinitroanthraquinone and l-chloro-2,8-dinitroanthraquinone. Since these isomers are similar in theirphysical and chemical properties, it is not necessary to isolate eithercompound from the mixture. The reaction product may be reduced directlyto the diamino compounds.

The nitration may be carried out by any of the known procedures. cessnitric acid on a solution of the 1-chlor-2-nitroanthraquinone insulfuric acid; but other procedures are known to the art and will givethe same compound. It is one of the advantages of this method, that noother isomers, polynitro compounds, or hydroxy compounds are formed,which are so common in nitrations of chloroanthraquinones. As long as anexcess of nitric acid is used, one .will get only the dinitro compound.

The reduction of the dinitro compound to the diamino compounds proceedswith great case. out by the action of mild alkaline reducing agents atquite low temperatures. Examples of such reducing agents are the alkalisulfides and hydrosulfides. Care must be taken in choosing conditionsthat the chlorine is not replaced, since it is highly reactive due tothe adjacent B-nitro group.

To utilize these diamines in the preparation of amino azoles, they areacylated. The carbonyl group of the acyl radical introduced in the2-amino position will eventually become part of the azole ring. Acylgroups which may be introduced by reaction of the diamine with an acylchloride include alkoyl, aroyl, and heterocyclic carboxyl residues. Theacylation is carried out at an elevated temperature in solution in ahigh-boiling, inert or- We have preferred to use the action of ex- Itcan be carried.

ganic solvent, with or Without the presence of an acid binding agent.Such an acid binding agent, however, increases the yield. The productsare usually isolated by filtration after coolingithe reaction mixtures."They are 5 yellow solids. v i

The utility of our new products now becomes apparent. Since an acylamino group is present ortho to a chlorine, it is only necessary, toconvert the chlorov derivative to a mercaptan in orderto ,form athiazole ring on the an-f; 10 thraquinone at thispoint- Similarly,substitution of hydroxyl for the chlorine will give an oxa zole, orsubstitue tion of an amino group will give an imidaozle. The mainnucleus of theacyl group becomes the -,u-substituent.in I

the azole ring .thus constructed.

does not, it is easily formed by heating the mixture in sulfuric acid, aprocedure necessary in any event, to free the other amino .g'roupoftheacyl substituent. When the acyl group used is benzoyl, deacylation insulfuric acid yields phenylthiazoloanthraquinonylamine.

Our invention can be illustrated by the following examples in which thepartsare by weight unless otherwise indicated. I

EXAMPLE 1 sevenp arts of l chlor-2-nitroanthraquinone was dissolved" in70 parts by volume of monohydrate. The so1u-- tion' was cooled to 5 Cfand four parts of a mixed acid of composition 52% nitric acid and48%sulfuric acid added gradually while keeping thesolution cold. Themixturewas allowed to warm to room temperature and stirred until thenitration was complete. The yellow sulfuric acid .slurry: was drownedand the precipitated lchlor- 2,5-dinitroanthraquinone and-l-chloro-2,8-dinitro-. yellow product anthraquinone filtered "and;washed. The when dry melted. at 206-212 C.

EXAMPLE 2 to remove the small amount of the by-product, 1-mercap-' 0to-2,S-diaminoanthraquinone. The isomeric mixture of1-chloro-diaminoanthraquinones so produced melted at 258-261" C. and wasa red solid.

Pgtented Sept. 6, 1955 Conversion :to thiazolescan be carriedzout byreaction 7 with sodium-disulfide in organic solvents. In many cases; thethiazole ring will form immediately in situ, but it it 3 EXAMPLE 31-chlor-2,5- (8 -dibenzoylaminaanthraquinone C1 ll a EXAMPLE 45-(8)-benz0ylamin0-1,Z-phenyIthiazoloanthraquinone A solution of sodiumdisulfide in aqueous pyridine was prepared by stirring and heating 37.5parts of pyridine, 8.5 parts of sodium sulfide, 2.28 parts of sulfur,and 6.25 parts by volume of water until a complete solution wasobtained. Ten parts of 1-chlor-2,5-(8)-dibenzoylaminoanthraquinone wasadded and the mixture stirred at 90-l00 C. until no starting materialwas detectable. The yellow-green slurry was drowned in water and theproduct isolated by filtration. The green-yellow solid can berecrystallized from nitrobenzene.

EXAMPLE 5 5-(8)-benz0ylamin0-1,Z-phenylthiazoloanthraquinone A solutionof sodium bisulfide in alcohol was prepared by stirring and heating fiveparts sodium sulfide'crysta'l's, 0.67 part sulfur and 150 parts byvolume of alcohol until a complete solution was obtained. Fiv'e parts ofl-chlor- 2,5-(8)-dibenzoylarninoanthraquinone was then added and themixture stirred and heated at reflux until the starting material was nolonger detectable. The mixture was drowned in water and the precipitateisolated by filtration. It was identical with the product obtained fromExample 4.

4 EXAMPLE 6 5- (8 -amin0-I,2-phenylth iazoloanthraquinone Two parts of5-(8)-beiizoylamino-1,2-pheriylthiazoloanthraquinone was heated inconcentrated sulfuric acid to C. The solution was drowned in Water andthe precipitated free amine isolated by filtration. It was a red solidwith a melting point, when dry, of approximately We claim: 1. Compoundshaving the formula:

in which X isahalogen, and Y is an u-substituent selected from the classconsisting of N02 and NH2 groups, and Z is the" same radical as Y.

2. Compounds having the formula:

in which Y is an a-nitro group.

3. Compounds having the formula:

in which Y is an a-amino group.

References Cited in the file of this patent FOREIGN PATENTS GreatBritain of 1899 GreatB'ritain Dec. 29, 1921

1. COMPOUNDS HAVING THE FORMULA: